Project Abstract Malaria due to Plasmodium vivax causes significant global morbidity and even mortality each year. However, it has long been considered absent from Sub-Saharan Africa due to the high prevalence of a mutation that confers the Duffy-negative phenotype and protects the host from infection. Although the Duffy-negative phenotype has been previously shown to be protective, recent reports from Sub-Saharan Africa have identified active transmission of P. vivax among Duffy-negative hosts. This indication that P. vivax can infect Duffy- negative hosts raises several questions, including where are infections occurring, who is being infected, where are these infections being sourced from, and finally, the history and extent of ongoing transmission. The objective of this proposal is to fill this critical gap in knowledge and provide public health officials with the information needed to form strategies for targeted interventions. In this proposal, we will use data collected by the Demographic Health Survey (DHS) during the 2013-2014 Standard DHS Survey of the Democratic Republic of the Congo (Study ID: DRC DHS-II). This nationally representative survey included approximately 25,000 adult men, women, and children across the DRC. From each individual, we have over 500 demographic and behavioral covariates, P. vivax malaria status, and geographical information. Using this robust dataset, the Specific Aims of this proposal are: (1) Map P. vivax prevalence and identify risk factors associated with infection in the Democratic Republic of the Congo using the 2013-2014 Demographic Health Survey and (2) Using whole genome sequencing, identify the source of infection and determine the extent of ongoing transmission among the Democratic Republic of the Congo P. vivax population. Through this research proposal and associated training plan, I will gain a unique and interdisciplinary skill-set that combines epidemiology with population genetics in an innovative manner that is at the forefront of infectious disease epidemiology. This training will provide me with the technical, statistical, and professional skills I need to become a leader at an academic center and to pursue my goals of practicing international medicine and research as a physician scientist.